Tilda Swinton performs 'The Maybe' at the Museum of Modern Art

Tilda Swinton performs the art of sleeping in her one-person piece called "The Maybe" at the Museum of Modern Art in Manhattan. Swinton, who first performed as a sleeper at the Serpentine Gallery in London in 1995, sleeps in a glass case for day. The case will move to locations throughout the museum every time Swinton performs. (March 25, 2013)

(Credit: AP)

Actress Tilda Swinton performs the art of sleeping in her one-person piece called "The Maybe" at the Museum of Modern Art in Manhattan. (March 25, 2013)

(Credit: AP)

Actress Tilda Swinton performs the art of sleeping in her one-person piece called "The Maybe" at the Museum of Modern Art in Manhattan. (March 25, 2013)

(Credit: AP)

Actress Tilda Swinton performs the art of sleeping in her one-person piece called "The Maybe" at the Museum of Modern Art in Manhattan. (March 25, 2013)